Trisiloxane

Catalog Number

ACM107517-3

CAS

107-51-7

Structure

Synonyms

Octamethyltrisiloxane;Trisiloxane, 1,1,1,3,3,5,5,5-octamethyl-;Trisiloxane, octamethyl-

Molecular Weight

236.53

Molecular Formula

C8H24O2Si3

Active Content

95%

Physical State

Liquid

Typical Applications

Use as solvent.
Use as lubricant.
Use as anti-foaming agent.

MSDS

Download MSDS

COA

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Spec Sheet

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Case Study

Octamethyltrisiloxane Used for the Preparation of Thermally Stable Working Fluids in Medium-High Temperature ORC Systems

Octamethyltrisiloxane Used for the Preparation of Thermally Stable Working Fluids in Medium-High Temperature ORC Systems Yu, W., Wang, S., Liu, C., Li, Q., & Xu, X. (2025). Energy, 320, 135017.

Octamethyltrisiloxane (MDM) is widely employed as a working fluid in medium-high temperature organic Rankine cycle (ORC) systems due to its favorable volatility and low viscosity. However, its thermal stability often limits practical applications. This study investigates the enhancement of MDM thermal stability through strategic methyl group substitutions, targeting improved performance in high-temperature ORC applications.
Experimental Approach:
Functional group substitutions were conducted on the central methyl of MDM using -C₂H₅, -C₆H₅, -OSi(CH₃)₃, -F, and -Cl. Density functional theory (DFT) and ReaxFF simulations predicted the effect of each substitution on Si-Si bond polarization, bond dissociation energies, and decomposition activation energies. MDM_OSi(CH₃)₃ emerged as the most promising derivative, increasing the apparent activation energy for decomposition by approximately 47.9 kJ·mol⁻¹. Thermal stress experiments validated these predictions, showing that MDM_OSi(CH₃)₃ maintained structural integrity up to 350 °C, nearly 100 °C higher than unmodified MDM, with decomposition products similar to MDM, including linear and cyclic siloxanes (MM, MD3M-MD6M, D3-D8). Significant decomposition occurred only above 400 °C, with molar retention remaining above 85 %.
Thermodynamic performance evaluation in regenerative ORC systems confirmed that MDM_OSi(CH₃)₃ delivers net power output, energy efficiency, and exergy efficiency comparable to MDM and MM.
These results demonstrate that functionalized octamethyltrisiloxane, particularly the trimethylsiloxy-substituted derivative, is a viable, thermally robust working fluid for medium-high temperature ORCs, offering enhanced stability without compromising cycle performance.

Octamethyltrisiloxane Used for the Preparation of Poly-Generation Systems for Power, Desalinated Water, and Process Heat Production

Octamethyltrisiloxane Used for the Preparation of Poly-Generation Systems for Power, Desalinated Water, and Process Heat Production Eveloy, Valérie, Peter Rodgers, and Linyue Qiu. Energy 98 (2016): 26-39.

Octamethyltrisiloxane (MDM) serves as an effective working fluid in organic Rankine cycles (ORC) applied to poly-generation systems, particularly in energy-intensive hydrocarbon production fields. Its favorable thermophysical properties enable efficient conversion of gas turbine exhaust thermal power into mechanical work, process heat, and freshwater generation via seawater reverse osmosis (RO).
Application Overview:
A poly-generation scheme was evaluated for an off-shore oil field in the Arabian Gulf, where MDM was used in a bottoming ORC to recover gas turbine exhaust heat. The recovered thermal energy drove an on-site RO unit while condenser heat supplied process hot water. The system yielded a net power output of 6 MW, 37 MW of process heat, and 1380 m³/h of desalinated water. The ORC achieved overall exhaust gas heat recovery efficiencies of approximately 10%, while the RO unit operated with a specific energy consumption of 4.1 kWh/m³ and an exergy efficiency of 29%.
Thermodynamic assessment indicated that the overall poly-generation system attained an exergetic efficiency of 32%, improving the original gas turbine cycle efficiency by 6%. The majority of exergy losses occurred in the intermediate gas-oil heat exchanger, ORC condenser, and RO high-pressure pump. Economic analysis projected profitability within three years under subsidized local water and natural gas prices, accounting for primary energy savings, freshwater generation, and avoided carbon emissions.
This study demonstrates that octamethyltrisiloxane is highly suitable for integrated poly-generation applications, enabling simultaneous production of electricity, thermal energy, and potable water while enhancing overall energy efficiency in industrial settings.

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